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From: jlg@cochiti.lanl.gov (Jim Giles)
Newsgroups: comp.lang.c
Subject: Re: low level optimization
Message-ID: <22025@lanl.gov>
Date: 19 Apr 91 22:59:22 GMT
References: <21703@lanl.gov> <1991Apr18.124836.5686@watmath.waterloo.edu> <21818@lanl.gov> <3905@inews.intel.com>
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> [...]     but why is it so horrible to you to document
> to the users of your optimized libraries that certain
> arguments to certain functions must be carefully
> non-aliased?  [...]

It's not horrible.  You miss my point if you believe that I would
oppose that.  You give me a portable way to declare to the compiler
that two (or more) arguments are assumed not to be aliased and I will 
rejoice.

The problem is that what people are recommending is _not_ portable
and is _not_ an explicit declaration (so the end user has to guess 
which variables the compiler optimized in this way and which are 
safe to alias).

J. Giles